Heat Recovery Device

ABSTRACT

A heat recovery device for use on a clothes dryer includes a body having a main passageway. The body has a first end and a second end and a dryer exhaust coupling proximate to the first end. The first end has a main flow inlet and the second end has a main flow outlet. The heat recovery device also includes a return air conduit coupled to the body. The return air conduit has a return air inlet and a return air outlet. The return air inlet is disposed within the main passageway and facing the main flow inlet. The dryer exhaust coupling is configured to be removably coupled to a dryer exhaust outlet of a clothes dryer. The return air inlet is configured to receive a portion of the exhaust air discharged from the clothes dryer and discharge that portion through the return air outlet.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 62/715,988, filed Aug. 8, 2018 (pending) and U.S.Provisional Patent Application Ser. No. 62/728,205, filed Sep. 7, 2018(pending), the disclosures of which are incorporated by reference hereinin their entirety.

TECHNICAL FIELD

The present invention relates to a heat recovery device for use with aclothes dryer.

BACKGROUND

Electric and gas heated clothes dryers have become common householdappliances during the past several decades for drying wet clothes insidea building, such as a house. As part of the typical clothes dryingprocess, the clothes dryer produces hot air. The hot air flows throughthe wet clothes and is then exhaust to the exterior of the house by wayof an exhaust vent. The practice of venting this hot exhaust air outsideis particularly inefficient and results in wasted energy, which mayresult in increased operating costs, especially in recent years with therapid rise in energy costs for homeowners. There are several problems,however, associated with simply venting the hot exhaust air from theclothes dryer directly back into the interior of the house which is whythe conventional practice is to vent the exhaust air to the exterior ofthe house. For example, the hot exhaust air from the dryer typicallycontains a certain amount of moisture and lint picked up from theclothes being dried. As a result, it is undesirable to re-circulate thehot exhaust air into the interior of the house or even back into thedryer.

What is needed, therefore, is a device and method for recovering atleast some of the driest hot air that would otherwise be exhausted tothe exterior of the house and redirecting that hot air either back intothe house or even the clothes dryer.

SUMMARY

A heat recovery device for use on a clothes dryer includes a body havinga main passageway with a central axis. The body has a first end and asecond end and a dryer exhaust coupling proximate to the first end. Thefirst end has a main flow inlet and the second end has a main flowoutlet. The heat recovery device also includes a return air conduitcoupled to the body. The return air conduit has a return air inlet and areturn air outlet. The return air inlet is disposed within the mainpassageway and facing the main flow inlet. The dryer exhaust coupling isconfigured to be removably coupled to a dryer exhaust outlet of aclothes dryer such that the exhaust air discharged from the clothesdryer flows into the main flow inlet. The return air inlet is configuredto receive a portion of the exhaust air discharged from the clothesdryer and discharge that portion through the return air outlet and aremainder of the exhaust air being discharged through the main flowoutlet.

In one embodiment, when the heat recovery device is coupled to the dryerexhaust outlet, the central axis is substantially horizontal. In thisembodiment, the return air outlet is configured to discharge the portionof the exhaust air from the clothes dryer in a direction substantiallyperpendicular to the central axis.

The return air inlet has a cross-section that is one of circular,semi-circular, elliptical, rectangular, square, or triangular.

In one embodiment, the return air inlet is disposed in an upper half ofthe main passageway.

In another embodiment, a heat recovery device for use on a clothesdryer, includes a body having a main passageway with a central axis. Thebody has a first end and a second end and a dryer exhaust couplingproximate to the first end. The first end has a main flow inlet and thesecond end has a main flow outlet. The heat recovery device alsoincludes a return air conduit integrally formed to the body. The returnair conduit has a return air inlet and a return air outlet. The returnair inlet is disposed within the main passageway and faces the main flowinlet and the return air outlet is disposed outside the main passageway.The body and the return air conduit are comprised of a first half and asecond half separable from each other along a plane extending throughthe central axis. The dryer exhaust coupling is configured to beremovably coupled to a dryer exhaust outlet of a clothes dryer such thatthe exhaust air discharged from the clothes dryer flows into the mainflow inlet. The return air inlet is configured to receive a portion ofthe exhaust air discharged from the clothes dryer and discharge thatportion through the return air outlet and a remainder of the exhaust airis discharged through the main flow outlet. In one embodiment, a portionof the return air conduit external to the body has a T-shaped profile.When the heat recovery device is coupled to the dryer exhaust outlet,the central axis may be substantially horizontal. In that configuration,the return air outlet is configured to discharge the portion of theexhaust air from the clothes dryer in a direction substantiallyperpendicular to the central axis.

In one embodiment, the heat recovery device further includes oneconnector affixed to the body and one connector affixed to the returnair conduit. Each connector is configured to couple together the firsthalf and the second half.

In another embodiment, the return air conduit includes a cover withopenings and the cover is coupled to the return air outlet. The covermay be slideably removable from the return air outlet and the openingsmay be elongated slots. The return air conduit may include openings onat least one side of the return air conduit. The return air inlet mayhave a semi-circular cross-section and the return air inlet is disposedin an upper half of the main passageway.

Other features of the heat recovery device are contemplated anddescribed and claimed below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate one or more exemplary embodimentsof the invention and, together with the general description of theinvention given above, and the detailed description of the embodimentsgiven below, serve to explain the embodiments of the invention.

FIG. 1 is side elevational view of the heat recovery device installed ona clothes dryer according to one embodiment of the invention.

FIG. 2 is a perspective view of the heat recovery device of FIG. 1.

FIG. 3 is a cross-sectional view of the heat recovery device of FIG. 2taken along line 3-3.

FIG. 4 is a perspective view of a heat recovery device according toanother embodiment of the invention.

FIG. 5 is a cross-sectional view of the heat recovery device of FIG. 4taken along line 5-5.

FIG. 6 is a perspective view of a heat recovery device according toanother embodiment of the invention.

FIG. 7 is a cross-sectional view of the heat recovery device of FIG. 6taken along line 7-7.

FIG. 8 is a perspective view of a heat recovery device according toanother embodiment of the invention.

FIG. 9 is a cross-sectional view of the heat recovery device of FIG. 8taken along line 9-9.

FIG. 10 is a front prospective view of a heat recovery device accordingto another embodiment of the invention.

FIG. 11 is rear prospective view of the heat recovery device of FIG. 10.

FIG. 12 is a cross-sectional perspective view of the heat recoverydevice of FIG. 10 taken along line 12-12 with the cover slid partiallyout.

FIG. 13 is a front elevational view of the heat recovery device of FIG.10.

FIG. 14 is a partial cross-sectional perspective view of the heatrecovery device of FIG. 10

FIG. 15 is a side elevational view of a clothes dryer exhausting dryerair to the exterior of a building.

FIG. 16 is a side elevational view of a clothes dryer exhausting dryerair to the interior of a building.

FIG. 17 is a cross-sectional view of the heat recovery device of FIG. 2with the inlet port located near the middle of the main passageway.

FIG. 18 is a cross-sectional view of the heat recovery device of FIG. 2with the inlet port located near the bottom of the main passageway.

DETAILED DESCRIPTION

The invention is intended to return heat, in the form of hot air, thatis normally exhausted from a conventional clothes dryer to the exteriorof a building, such as a house, and into the environment. According toone aspect of the invention, at least some of the hot air may bereturned to the interior of the house, such as into the room where theclothes dryer is located, to heat at least part of the interior of thehouse. According to another aspect of the invention, at least some ofthe hot air may be returned back into the clothes dryer to enhance thedrying efficiency of the clothes dryer. According to one aspect of theinvention, little or none of the moisture and lint which may beentrained in the exhausted hot air from the clothes dryer is returned tothe interior of the house or the clothes dryer.

With reference to FIG. 1, an exemplary laundry room 10 with aconventional clothes dryer 12 is illustrating venting hot exhaust airfrom the clothes dryer 12 to the exterior of a building 14, such as ahouse. A heat recovery device 20 according to one exemplary embodimentis shown coupled at one end to a dryer exhaust outlet 22 of the clothesdryer 12 and coupled at another end to an exhaust duct 24 which isrouted through an exterior wall 26 of the building 14. Hot exhaust air28 flowing through the exhaust duct 24 exits through a vent 30. Aconduit 32, such as pipe or tube, is coupled to the heat recovery device20. According to an aspect of the invention, return hot air 34 exits theconduit 32 into the interior of the house 14 as illustrated in FIG. 1.Alternatively, return hot air 34 may also exit into the clothes dryer 12instead of the interior of the house 14 according to another aspect ofthe invention.

Various embodiments of heat recovery devices are shown in FIGS. 2-12.Some features of the various embodiments of the heat recovery devices inFIGS. 2-12 are the same or nearly the same. Consequently, the samereference number for such a feature will be used on each embodimentwhere appropriate.

The heat recovery device 20 is further illustrated in FIGS. 2 and 3. Theheat recovery device 20 is comprised of a body 40 having a mainpassageway 42 with a main flow inlet 44 and main flow outlet 46. Themain flow inlet 44 includes a dryer exhaust coupling 48, which isconfigured to be coupled in sealing engagement to the dryer exhaustoutlet 22 of the clothes dryer 12. The exhaust duct 24 is coupled insealing engagement with the main flow outlet 46 of the heat recoverydevice 20. The heat recovery device 20 further includes a return airconduit 50 having a return air inlet 52 and a return air outlet 54,which is in sealing engagement with the conduit 32. The return air inlet52 is positioned in the main passageway 42, and more particularly, nearthe top of the main passageway 42. The return air conduit 50 and itsreturn air inlet 52 and return air outlet 54 have a generally circularcross-section, but could have other cross-sectional shapes as will bediscussed below.

With specific reference to FIG. 2, the flow path of the hot exhaust airfrom the clothes dryer 12 through the heat recovery device 20 isillustrated. Hot exhaust air being discharged from the dryer exhaustoutlet 22 flows into the main flow inlet 44 and into the main passageway42 as schematically indicated by arrow A. A portion of the hot exhaustair exits through the main flow outlet 46 as schematically indicated byarrow B. The remainder of the hot exhaust air exits through the returnair outlet 54 as schematically indicated by arrow C.

As shown in FIGS. 2 and 3, the body 40 of the heat recovery device 20 iscylindrical in shape, and sized such that the dryer exhaust coupling 48and body 40 have similar cross-sectional areas compared to the dryerexhaust outlet 22. However, the body 40 and the dryer exhaust coupling48 of the heat recovery device 20 are not limited to these shapes. Thedryer exhaust coupling 48 may be threaded or may be sized to produce africtional or interference fit with the dryer exhaust outlet 22 of theclothes dryer 12 to couple in sealing engagement with the dryer exhaustcoupling 48 of the heat recovery device 20. Similarly, the main flowoutlet 46 of the heat recovery device 20 may be sized to produce africtional or interference fit with the exhaust duct 24. It will beappreciated that tape, a pipe clamp, zip ties, screws, rivets, or othermechanical fasteners may be used to couple the heat recovery device 20to the dryer exhaust outlet 22 and the exhaust duct 24. In oneembodiment (FIG. 5), the heat recovery device 20 is constructed ofpolyvinyl chloride (PVC), but it may be constructed of any othersuitable plastic, rubber, carbon-fiber, metal, or any other suitablematerial. Moreover, the components of the heat recovery device 20 mayeach be constructed of different materials as operating conditionswarrant. For example, the body 40 may be constructed of PVC while thereturn air conduit 50 may be constructed of metal.

The return air inlet 52 of the heat recovery device 20 in FIGS. 2 and 3has a circular cross-section with a diameter which is smaller than thediameter of the circular cross-section of the main passageway 42 of thebody 40. In the embodiment in FIG. 3, the diameter of return air inlet52 is a little more than one-third the diameter of main passageway 42 ofthe body 40. By way of example, but not a limitation, the diameter ofreturn air inlet 52 may range from between one-tenth to three-quartersof the diameter of the main passageway 42 of the body 40. The size andlocation of the return air inlet 52 may be dictated by how much moistair is desired to be directed back into the laundry room 10. Forinstance, someone in drier climates may want more of the moist airdirected back into the interior of the house 14. To that end, a largerreturn air inlet 52 positioned lower in the body 40 may likely returnmore moist air back into the interior of the house 14 and a smallerreturn air inlet 52 positioned at the top of the main passageway 42 ofthe body 40 may likely return less moist air back into the interior ofthe house 14.

In the embodiment of the heat recovery device 20 shown in FIGS. 2 and 3,the return air inlet 52 is sized to remain in the upper half of the mainpassageway 42 of the body 40 to capture the dry hot air while the moistair and lint particulates pass under return air inlet 52 and areexhausted to the exterior of the building 14 via the exhaust duct 24. Itis believed that placing the return air inlet 52 in the upper-half ofthe main passageway 42 of the body 40 will return the driest air fromthe dryer exhaust outlet 22 back into the laundry room 10. In addition,the force of the exhaust airstream exiting from the exhaust outlet 22 isadequate to separate and return the dry air via the return air conduit50 into the laundry room 10. As a result, no additional energy isconsumed to recover the dry air from the exhaust stream.

Different shapes and configurations of the return air inlet 52 of thereturn air conduit 50 would be apparent to one skilled in the art inorder to alter the amount of warm air recovered. As such, the shapes andconfigurations are not limited to the shapes and configurationsdisclosed herein. In one embodiment shown in FIGS. 4 and 5, the heatrecovery device 20 includes a return air conduit 60 with a return airinlet 62 having a flat surface 64 located in the upper-half of the mainpassageway 42 of the body 40 and just below where the return air conduit60 intersects with the body 40. The flat surface 64 may be located atdifferent positions relative to the top of the main passageway 42 of thebody 40 to change the amount of hot air returned to laundry room 10 viaconduit 32. The closer the flat surface 64 is to the top of the mainpassageway 42 of the body 40 (e.g., around 25% of the diameter of themain passageway 42 from the top), the less hot air that may be directedinto the interior of the laundry room 10. Conversely, the further theflat surface 64 is from the top of the main passageway 42 body 40 (e.g.,around 75% of the diameter of the main passageway 42 from the top) thewarmer air may be directed into the interior of the laundry room 10. Theflat surface 64 is shown mounted to the sidewalls of the main passageway42 of the body 40 with a flat, half-moon shaped back portion 66, curvedto couple it to the upper-half of the main passageway 42.

In another embodiment shown in FIGS. 6 and 7, the heat recovery device20 includes a return air conduit 70 with a return air inlet 72 that hasan elliptical cross-section. The upper-half of the ellipticalcross-section of the return air inlet 72 generally mimics the shape ofthe main passageway 42 of the body 40 of the heat recovery device 20.

In yet another embodiment shown in FIGS. 8 and 9, the heat recoverydevice 20 includes a return air conduit 80 with a return air inlet 82that has a rectangular cross-section. The return air inlet 82 may alsohave a square cross-section. In another embodiment, the cross-section ofthe return air inlet may have triangular cross section.

Another embodiment of a heat recovery device 90 is shown in FIGS. 10-14.The heat recovery device 90 is comprised of a body 92 having a mainpassageway 94 with a main flow inlet 96 and a main flow outlet 98. Themain flow inlet 96 includes a dryer exhaust coupling 100 formed from aseries of tabs 102, which are configured to be coupled in sealingengagement to the dryer exhaust outlet 22 of the clothes dryer 12. Thetabs 102 may be flexible to allow the dryer exhaust coupling 100 to slipover the dryer exhaust outlet 22 to produce a frictional or interferencefit. It will be appreciated that tape, a pipe clamp, zip ties, screws,rivets, or other mechanical fasteners may be used to couple the heatrecovery device 90 to the dryer exhaust outlet 22 and the exhaust duct24. The heat recovery device 90 further includes a return air conduit104 having a return air inlet 106 and a return air outlet 108. In oneembodiment, the return air conduit 104 is integrally formed with thebody 40. While the return air inlet 106 shown in FIG. 13 has asemi-circular cross-section, other cross-sectional geometries may beused, including but not limited to circular, elliptical, rectangular,square, or triangular. While the portion of the return air conduit 104that is external to the body 92 has a generally T-shaped profile as seenin FIG. 13, other profiles may be implemented. The return air outlet 108has a generally rectangular shape with a slidable cover 110 withopenings 112, such as elongated slots, fit thereover. The cover 110 maybe slid partially off or completely removed the return air outlet 108 sothat the interior of the return air conduit 104 may be cleaned or toallow greater airflow through the return air outlet 108. The return airconduit 104 has opposing sides 114, 116, with openings 118, such aselongated slots. The slots 112 and the slots 118 are configured to allowreturn hot air flow through them. It will be appreciated that the returnair outlet 108 may have other shapes such a square or circular, forexample. It will be further appreciated that through holes and othertypes of openings may be used in place of the slots 112 and/or the slots118 to allow return hot air to flow through them. As shown in FIG. 13,the bottom of the return air inlet 106 is located approximatelyone-third of the diameter of the main passageway 94 from the top of themain passageway 94. In other words, the return air inlet 106 is disposedwithin the upper portion of the main passageway 94.

With specific reference to FIG. 10, the flow path of the hot exhaust airfrom the clothes dryer 12 through the heat recovery device 90 isillustrated. Hot exhaust air flows through the main flow inlet 96 andinto the main passageway 94 as indicated by arrow A. A portion of thehot exhaust air exits through the main flow outlet 98 as indicated byarrow B. A portion of the hot exhaust air exits through the return airoutlet 108, and more specifically through the slots 112 of the cover110, as indicated by arrow C. A portion of the hot exhaust air exitsthrough the slots 118 in opposing sides 114, 116, as indicated by arrowsD. Unlike the embodiments illustrated in FIGS. 2-9, the return airconduit 104 is not connected to a conduit, such as conduit 32, to directthe return hot air into the laundry room 10. Instead, the return hot airenters the laundry room 10 immediately after exiting through the slots112, 118.

In an exemplary embodiment, the heat recovery device 90 may beconstructed of two, separate halves 120, 122, which are held together bythree connectors 124, two on the return air conduit 104 (FIGS. 10, 11)and one on the bottom of body 92 (FIGS. 13, 14). In one embodiment, thetwo halves 120, 122 are joined to each other along a plane extendingthrough the central axis of the main passageway 94. Each connector 124includes a flexible member 126 with a retaining member 128 at its distalend. The flexible member 126 is coupled to side 122 of the heat recoverydevice 90. A coupling member 130 is coupled to side 120 of the heatrecovery device 90. As the two halves 120, 122 are move toward eachother, the retaining member 128 contacts the coupling member 130 andflexes away from the coupling member 130 as the two halves 120, 122continue to be moved toward each other. As the two halves 120, 122engage one another, the retaining member 128 moves past the couplingmember 130 the flexible member 126 returns to it undeflected positionand retaining member 128 engages the coupling member 130 to hold the twohalves 120, 122 of the heat recovery device 90. It will be appreciatedthat other connectors may be used to hold the two halves 120, 122together, such as screws, nuts and bolts, adhesive, glue, etc. It willalso be appreciated that the body 92 of the heat recovery device 90 maybe formed as a single, monolithic structure, i.e., as one piece.

Each embodiment of the heat recovery devices 20, 90 discussed aboveincludes a main passageway 42, 94, which has a central axis.Advantageously, in practice, the heat recovery devices 20, 90 will becoupled to the clothes dryer 12 such that the central axes of the mainpassageways 42, 94 are substantially horizontal and each of the returnair outlets 54, 108 discharge return air substantially perpendicular tothe central axis in a substantially vertical direction.

As mentioned above, the position of the return air inlet in the mainpassageway is likely to influence the amount of moisture in the returnedhot air being discharged into the laundry room. That is, the return airinlet may be positioned to collected drier air or positioned to collectmoister air. To evaluate the position of the return air inlet on theamount of moist in the returned hot air, the inventor conducted fivetests. The five tests were conducted to evaluate how the temperature andhumidity inside a laundry room containing a conventional, electricresidential clothes dryer changed under varying venting configurations.The five tests were conducted in a laundry room measuring 5 feet by 6feet with the laundry room door closed. Each test began with removingfive beach towels from conventional, residential clothes washing machineafter completing a normal wash cycle and placing them into the clothesdryer. The dryer was run for 30 minutes on the high heat setting. Atemperate and humidity monitor made by ACU RITE™ sitting directly on thetop center of the dryer was used to measure temperature and humidityimmediately before and immediately after the drying cycle. None of thedryer exhaust was diverted back into the dryer during any of the fivetests.

In Test No. 1, the dryer exhaust was vented directly to the outside likea typical clothes dryer is usually set-up and operated as schematicallyillustrated in FIG. 15. That is, a heat recovery device of the typediscussed above was not used and no dryer exhaust was intentionallydiverted into the laundry room.

In Test No. 2, all of the dryer exhaust was vented directly into thelaundry room as schematically illustrated in FIG. 16. In other words,nothing was attached to the dryer exhaust pipe.

In Test No. 3, the heat recovery device 20 similar to the one shown inFIGS. 2 and 3 was used. The dryer exhaust coupling 48 of the heatrecovery device 20 was attached to the dryer exhaust outlet 22 and themain flow outlet 46 of the heat recovery device 20 was attached to theexhaust duct 24 which was attached to the vent 30. The return airconduit 50 was positioned such that return air inlet 52 was in the mostupwardly vertical position in the main passageway 42 of the body 40 ofthe heat recovery device 20 as illustrated in FIG. 3. In thisconfiguration, a portion of the dryer exhaust exited through the vent 30and a portion of the dryer exhaust exited the return air conduit 50 intothe laundry room.

In Test No. 4, the heat recovery device 20 was connected to the clothesdryer in the same manner as in Test 3, but the return air conduit 50 waspositioned such that the centerline of the return air inlet 52 wasconcentric with the centerline of the main passageway 42 of the body 40of the heat recovery device 20 as illustrated in FIG. 17. Like Test No.4, a portion of the dryer exhaust exited through the vent 30 and aportion of the dryer exhaust exited the return air conduit 50 into thelaundry room.

In Test No. 5, the heat recovery device 20 was connected to the clothesdryer in the same manner as in Test 3, but the return air conduit 50 waspositioned in the most vertically downward position in the mainpassageway 42 of the body 40 of the heat recovery device 20 asillustrated in FIG. 18. Again, a portion of the dryer exhaust exitedthrough the vent 30 and a portion of the dryer exhaust exited the returnair conduit 50 into the laundry room.

The table below summarizes the data that the temperate and humiditymonitor collected during the five tests.

Starting Ending Temp. Starting Ending Humidity Test Test Temp. Temp.Change Humidity Humidity Change No. Description (F.) (F.) (F.) (%) (%)(%) Comments 1 Typical 75 77 +2 45 46 +1 No visible connection moistureon walls or ceiling of laundry room 2 Venting 75 111 +36 42 99 +57 Wallsdirectly to showed laundry visible room wetness. Ceiling showedsignificant wetness, including beads of water. 3 Inlet port in 75 82 +745 49 +4 No visible top position moisture on walls or ceiling of laundryroom 4 Inlet port in 75 80 +5 43 53 +10 No visible middle moisture onposition walls or ceiling of laundry room 5 Inlet port in 75 81 +6 41 57+16 Slightly bottom visible position wetness on walls and ceiling.

When looking at the data from Test Nos. 3-5, Test No. 3 yielded thegreatest temperature gain, a rise of 7 degrees, and the lowest increasein humidity, a rise of 4 percentage points. Test No. 5 yielded thehighest increase in humidity, 16 percentage points.

While the present invention has been illustrated by a description ofvarious preferred embodiments and while these embodiments have beendescribed in some detail, it is not the intention of the inventor torestrict or in any way limit the scope of the appended claims to suchdetail. Additional advantages and modifications will readily appear tothose skilled in the art. Thus, the various features of the inventionmay be used alone or in any combination depending on the needs andpreferences of the user.

What is claimed is:
 1. A heat recovery device for use on a clothesdryer, comprising: a body having a main passageway with a central axis,the body having a first end and a second end and a dryer exhaustcoupling proximate to the first end, the first end having a main flowinlet and the second end having a main flow outlet; and a return airconduit coupled to the body, the return air conduit having a return airinlet and a return air outlet, the return air inlet disposed within themain passageway and facing the main flow inlet; wherein the dryerexhaust coupling is configured to be removably coupled to a dryerexhaust outlet of a clothes dryer such that the exhaust air dischargedfrom the clothes dryer flows into the main flow inlet, and wherein thereturn air inlet is configured to receive a portion of the exhaust airdischarged from the clothes dryer and discharge that portion through thereturn air outlet and a remainder of the exhaust air being dischargedthrough the main flow outlet.
 2. The heat recovery device of claim 1,wherein when the heat recovery device is coupled to the dryer exhaustoutlet, the central axis is substantially horizontal.
 3. The heatrecovery device of claim 2, wherein the return air outlet is configuredto discharge the portion of the exhaust air from the clothes dryer in adirection substantially perpendicular to the central axis.
 4. The heatrecovery device of claim 1, wherein the return air inlet has across-section that is one of circular, semi-circular, elliptical,rectangular, square, or triangular.
 5. The heat recovery device of claim1 wherein the return air inlet is disposed in an upper half of the mainpassageway.
 6. The heat recovery device of claim 1, wherein the returnair conduit includes a cover with openings, the cover coupled to thereturn air outlet.
 7. The heat recovery device of claim 6, wherein thecover is slideably removable from the return air outlet and the openingsare elongated slots.
 8. The heat recovery device of claim 6, wherein thereturn air conduit includes openings on at least one side of the returnair conduit.
 9. A heat recovery device for use on a clothes dryer,comprising: a body having a main passageway with a central axis, thebody having a first end and a second end and a dryer exhaust couplingproximate to the first end, the first end having a main flow inlet andthe second end having a main flow outlet; and a return air conduitintegrally formed to the body, the return air conduit having a returnair inlet and a return air outlet, the return air inlet disposed withinthe main passageway and facing the main flow inlet, the return airoutlet disposed outside the main passageway; wherein the body and thereturn air conduit are comprised of a first half and a second halfseparable from each other along a plane extending through the centralaxis, wherein the dryer exhaust coupling is configured to be removablycoupled to a dryer exhaust outlet of a clothes dryer such that theexhaust air discharged from the clothes dryer flows into the main flowinlet, and wherein the return air inlet is configured to receive aportion of the exhaust air discharged from the clothes dryer anddischarge that portion through the return air outlet and a remainder ofthe exhaust air being discharged through the main flow outlet.
 10. Theheat recovery device of claim 9, further comprising one connectoraffixed to the body and one connector affixed to the return air conduit,each connector configured to couple together the first half and thesecond half.
 11. The heat recovery device of claim 9, wherein a portionof the return air conduit external to the body has a T-shaped profile.12. The heat recovery device of claim 9, wherein the return air conduitincludes a cover with openings, the cover coupled to the return airoutlet.
 13. The heat recovery device of claim 12, wherein the cover isslideably removable from the return air outlet and the openings areelongated slots.
 14. The heat recovery device of claim 12, wherein thereturn air conduit includes openings on at least one side of the returnair conduit.
 15. The heat recovery device of claim 9, wherein the dryerexhaust coupling is formed from a plurality of flexible tabs configuredto be removably coupled to the dryer exhaust outlet of the clothesdryer.
 16. The heat recovery device of claim 9, wherein the return airinlet has a semi-circular cross-section and the return air inlet isdisposed in an upper half of the main passageway.
 17. The heat recoverydevice of claim 9, wherein when the heat recovery device is coupled tothe dryer exhaust outlet, the central axis is substantially horizontal.18. The heat recovery device of claim 17, wherein the return air outletis configured to discharge the portion of the exhaust air from theclothes dryer in a direction substantially perpendicular to the centralaxis.